Canadian writer-director Kim Nguyen's fourth feature film stars young Congolese actress Rachel Mwanza, who was abandoned by her parents at age 6 and fended for herself on the streets of Kinshasa.

A decade ago, Canadian writer-director Kim Nguyen started working on the script that would become "War Witch," a film about a girl in sub-Saharan Africa who is kidnapped by rebels, conscripted as a child soldier and forced to commit horrific acts of violence.

Around the same time, Rachel Mwanza was abandoned by her parents in the Democratic Republic of the Congo at age 6, living with her grandmother for a time and then fending for herself on the streets of Kinshasa, the capital.

Nguyen was finally able to put his film into production in 2011 and cast Mwanza in the title role. The experience has profoundly affected them both: "War Witch" has led to a caregiver and an education for Mwanza, now 16, and the movie, opening Friday in L.A., was nominated for an Academy Award for foreign-language film. (It is in French and Lingala.)

For Nguyen, the film is less about war and child soldiers than it is about an ordinary girl in extraordinary circumstances. "She's a child, she's an adult, she's a killer, she's a victim, and I thought that the film medium lended itself well to this," the director, 38, said in an interview on the pool deck of a Beverly Hills hotel.

"War Witch" is Nguyen's fourth feature. After his third film, 2010's "La Cite" (The City of Shadows), he felt "a little bit jaded by all the pressures of industry," he said. "Fitting all the check boxes for a script makes them kind of constrained."

His inspiration for "War Witch" came from an article about Johnny and Luther Htoo, young Burmese twins who led a guerrilla group known as God's Army in the 1990s and were believed by their followers to have magic powers. Early in Nguyen's research, the Montreal native shifted his focus to Africa and began developing the character that Mwanza would inhabit: Komona, who is torn from her small village by rebels and deemed a sorceress after being the only survivor of a deadly shootout.

With a $3.7-million budget largely financed by the cultural agencies Telefilm Canada and SODEC, Nguyen scouted locations in Congo, Cameroon and Kenya. "Kenya had by far the best filming capabilities," he said, "but the DRC was just this very powerful, idiosyncratic country that you couldn't imitate."

"War Witch" (also known by its French title, "Rebelle") was shot entirely in Congo in July 2011.

There is little filmmaking infrastructure in the war-torn nation, which has a long history of civil strife and corruption. During the Cold War, the U.S.-backed despot Mobutu Sese Seko ruled the country, then known as Zaire, and not long after his ouster in 1997, conflicts ignited between government forces supported by Angola, Namibia and Zimbabwe and rebels backed by Rwanda and Uganda. Since then, more than 5 million people have died from violence, poverty and disease. Despite the signing of peace accords, fighting persists in the east of the country, and Congo currently hosts one of the largest U.N. peacekeeping forces.

"You have to be a little bit crazy to go and shoot a feature film in Congo, that's what everybody told us," producer Pierre Even said by phone from Montreal. "It's a survival economy where anything that you need, you need to negotiate, and it's a cash economy as well … nobody will give you anything if you don't pay first."

Safety was also a constant concern. The cast and crew stayed in what Nguyen described as "luxury bunkers" — hotels fortified with huge gates, barbed wire and electronic doors. They always traveled in cars with security detail.

Filming on location and working with a cast composed largely of inexperienced young actors gave "War Witch" a raw beauty, especially as captured by cinematographer Nicolas Bolduc. (Nguyen credits the film's atmospheric lighting to the haze created by the ubiquitous heaps of burning tires in the country.)

Nguyen shot the film in sequence and didn't have the cast read the script beforehand, instead revealing scenes a day at a time. Working in a combination of French (the official language of Congo), and the main local language of Lingala (via an interpreter), Nguyen would describe the scenes to the actors and work in directed improvisations. The approach made practical sense, as some actors, including Mwanza, couldn't read, but Nguyen said it also gave the performances a sense of authenticity.

"They didn't have to fake anticipation because they didn't know what was going to happen," the director said.

The young Congolese actors were "courageous and fearless in the way they would act," Nguyen said, none more so than Mwanza, who stood out among a casting call that saw 3,000 youths. The filmmakers first heard of her through the Belgian documentary-fiction hybrid "Kinshasa Kids," which Mwanza appeared in and which shared some crew members with "War Witch."